Seminarium Teorii Oddziaływań Elementarnych

We present the state of the art of model building in the context of heterotic string compactifications on orbifolds. We show the details of a specific model having the MSSM chiral spectrum, with SU(5) unification at an energy scale set by the compactification scale. We also show how to link orbifold constructions to smooth manifold compactifications, and why this is crucial in the study of the phenomenological properties of a model.